Detonating Cord Retaining Device

ABSTRACT

An apparatus and method for connecting a detonating cord with a shaped charge.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.62/147,340, filed Apr. 14, 2015.

FIELD

This disclosure generally relates to perforating guns used in asubterranean environment such as an oil or gas well. More particularly,it relates to fittings and retainers that aligns the detonating cordwith a shaped charge installed in a charge tube. The embodimentsdisclosed have a retainer feature which allows for simplifiedinstallation with existing shaped charges and detonating cord.

BACKGROUND

Generally, when completing a subterranean well for the production offluids, minerals, or gases from underground reservoirs, several types oftubulars are placed downhole as part of the drilling, exploration, andcompletions process. These tubulars can include casing, tubing, pipes,liners, and devices conveyed downhole by tubulars of various types. Eachwell is unique, so combinations of different tubulars may be loweredinto a well for a multitude of purposes.

A subsurface or subterranean well transits one or more formations. Theformation is a body of rock or strata that contains one or morecompositions. The formation is treated as a continuous body. Within theformation hydrocarbon deposits may exist. Typically a wellbore will bedrilled from a surface location, placing a hole into a formation ofinterest. Completion equipment will be put into place, including casing,tubing, and other downhole equipment as needed. Perforating the casingand the formation with a perforating gun is a well known method in theart for accessing hydrocarbon deposits within a formation from awellbore.

Explosively perforating the formation using a shaped charge is a widelyknown method for completing an oil well. A shaped charge is a term ofart for a device that when detonated generates a focused explosiveoutput. This is achieved in part by the geometry of the explosive inconjunction with an adjacent liner. Generally, a shaped charge includesa metal case that contains an explosive material with a concave shape,which has a thin metal liner on the inner surface. Many materials areused for the liner; some of the more common metals include brass,copper, tungsten, and lead. When the explosive detonates the liner metalis compressed into a super-heated, super pressurized jet that canpenetrate metal, concrete, and rock.

A perforating gun has a gun body. The gun body typically is composed ofmetal and is cylindrical in shape. Within a typical gun tube is a chargeholder or carrier tube, which is a tube that is designed to hold theactual shaped charges. The charge holder will contain cutouts calledcharge holes where the shaped charges will be placed.

A shaped charge is typically detonated by a booster or igniter. Shapedcharges may be detonated by electrical igniters, pressure activatedigniters, or detonating cord. One way to ignite several shaped chargesis to connect a common detonating cord that is placed proximate to theigniter of each shaped charge. The detonating cord is comprised ofmaterial that explodes upon ignition. The energy of the explodingdetonating cord can ignite shaped charges that are properly placedproximate to the detonating cord. Often a series of shaped charges maybe daisy chained together using detonating cord.

SUMMARY OF EXAMPLE EMBODIMENTS

In order to detonate a shaped charge in a perforating gun a continuousdetonating cord is placed adjacent to each shaped charge. Holding adetonating cord in place is crucial to ensuring that all of the shapedcharges detonate when the detonating cord detonates. Otherwise,unexploded ordinance may end up being brought to the surface, causing aserious safety issue. Furthermore, current means of fastening the shapedcharge to the detonating cord require multiple cumbersome means.

An example embodiment may include a shaped charge retainer having anadaptor for holding a shaped charge, a first interface adapted to engagea charge holder, and a second interface adapted to engage a detonatingcord. It may include a third interface adapted to engage a shapedcharge. The first interface may have an oblong shape for translatinginto a matching oblong shaped cutout in the charge holder in a firstorientation. The rotation of the shaped charge to a second orientationmay substantially eliminate at least one degree of freedom of the shapedcharge retainer. The shaped charge retainer may prevent disengaging viathe inference of the first interface. The second interface may be aclamp for engaging to a detonating cord by rotating it relative to thedetonating cord. The second interface may include a plurality of clamps.The second interface may be a u-shaped retainer. The second interfacemay be a c-shaped retainer. The second interface may include one or moreprotrusions adapted to restrain a detonating cord. The first interfacemay have an oblong shape. The first interface may have a non-circularshape. The first interface may be circular in shape. The first interfacemay be oblong in shape. The first interface may be polygon in shape. Thefirst interface may be threaded. The first interface may be integrallyformed to the charge holder. The third interface may be adapted to snaponto the end of a shaped charge. The third interface may be adapted tothread onto the end of a shaped charge. The third interface may beadapted to mechanically fasten to a shaped charge.

Another example embodiment is a detonating cord retainer having a bottomportion adapted to interface with the bottom of shaped charge. Generallythe shaped charge end will have a lip or other relevant feature that canbe secured to. The bottom portion of the retainer will have acorresponding flange or other snapping mechanism that can fit over thelip of the shaped charge. Once the retainer is attached to the shapedcharge, the shaped charge can be installed in a charge tube. The chargetube is a device adapted to contain the shaped charges in a perforatinggun. The charge tube will generally have a large hole for fitting theshaped charge through and a smaller hole, radially opposite the largehole, for the retainer to fit through. The retainer in this example canhave a unique shape that will match with a similar unique shaped cutoutin the charge tube. After the retainer is fitted through the uniqueshaped hole, it can be rotated, in this case 45 degrees, such that theretainer is in interference with the charge tube and cannot bedisengaged. Further, there can be locking features on the retainer thatengage additional cutouts on the charge tube to prevent the retainerfrom rotating once locked.

The first part is the installation of the retainer onto the shapedcharge and then installing the combination into a charge tube. Thesecond portion of the device disclosed is a detonating cord restrainingmechanism located on the top of the retainer. In this example, therestraining mechanism includes two arches shaped to allow detonatingcord to fall into place when the retainer is in the unlocked position.When the retainer is rotated as described above to lock into the chargetube, the orientation of the two arches changes with respect to thedetonating cord such that the detonating cord is locked into place inthe retainer.

A variation of the examples disclosed may include a charge tube having acharge hole cutout adapted to fit a shaped charge within the chargetube, a shaped charge retaining cutout, and a first locking cutout. Thefirst locking cutout is located adjacent to the shaped charge retainingcutout.

Examples may also have the shaped charge retaining cutouts adapted tofit a shaped charge retaining fitting. The shaped charge retainingcutout may be located 180 degrees opposite of the charge hole cutout.Examples may include a plurality of charge hole cutouts in a variety oforientations with respect to each other, sometimes referred to as phaseangle. A plurality of shaped charge retaining cutouts would go alongwith a plurality of charge hole cutouts. The retaining cutouts wouldinclude one or more locking cutouts located nearby each retainingcutout. The shaped charge retaining cutouts may have an irregular shapesuch that only one orientation of a retaining fitting would fit throughthe retaining cutout. One possible shape for the retaining cutout is anirregular hexagonal shape. The locking cutouts may have circular,rectangular, or irregular shapes. Some embodiments would include atleast two locking cutouts for each retaining cutout, located on twodifferent sides of each retaining cutout. The first locking cutout andthe shaped charge retaining cutout are oriented such that a shapedcharge retainer rotates in order to lock into place.

Another example embodiment includes a shaped charge retainer having abase portion with an opening adapted to attach to a shaped charge, abody portion adapted to accept a detonating cord, and a detonating cordretainer portion. The base portion has a flange adapted to engage ashaped charge. The base portion has a cutout adapted to allow the baseportion to snap onto a shaped charge. The body portion may furthercomprise a first rectangular portion and a second rectangular portionsubstantially parallel to the first rectangular portion. The firstrectangular portion may be longer than the second rectangular portion.The detonating cord retainer portion further may include a firstdetonating cord retainer. The detonating cord retainer portion mayinclude a second detonating cord retainer. The first rectangular portionmay include a fillet. The second rectangular portion may contain afillet. The first detonating cord retainer may contain an arch. Thesecond detonating cord retainer may contain an arch. The firstdetonating cord retainer and the second detonating cord retainer may beare adapted to accept a detonating cord at a first angle with respect toan axis formed by the substantially parallel first rectangular portionand the second rectangular portion. The apparatus may be adapted tosubstantially restrain the detonating cord when rotated a second angle.

Another example embodiment may include a method for securing adetonating cord to a shaped charge having installing a retainer fittingonto the end of a shaped charge, installing the shaped charge into acharge tube, installing a detonating cord onto the retainer fitting, androtating the retainer fitting a predetermined number of degrees. Themethod may include locking the retainer fitting onto the charge tube.The retainer fitting may be rotated approximately 45 degrees. Theretainer fitting may be snapped onto place on the shaped charge. Theshaped charge may be locked into place on the charge tube.

Another example embodiment may include a perforating gun having a chargetube, a plurality of shaped charges, in which each shaped charge has aretainer fitting, the shaped charge retainer fitting further having abase portion with an opening adapted to attach to a shaped charge, afirst rectangular portion and a second rectangular portion, in which thefirst rectangular portion is substantially parallel to the secondrectangular portion, a first detonating cord retainer and a seconddetonating cord retainer, and a locking mechanism. The base portion mayhave a flange adapted to engage a shaped charge. The base portion mayhave a cutout adapted to allow the base portion to snap onto a shapedcharge. The first rectangular portion could be longer than the secondrectangular portion. The first rectangular portion may contain a fillet.The second rectangular portion may contain a fillet. The firstdetonating cord retainer may contain an arch. The second detonating cordretainer may contain an arch. The first detonating cord retainer and thesecond detonating cord retainer may be adapted to accept a detonatingcord at a first angle with respect to an axis formed by thesubstantially parallel first rectangular portion and the secondrectangular portion. The apparatus may be adapted to substantiallyrestrain the detonating cord when rotated a second angle.

Another example embodiment may include a perforating gun system having ameans for containing a plurality of shaped charges, a charge tube, ameans for locating a detonating cord proximate to a shaped charge, and arotational means for securing the detonating cord to the shaped charge.The means for containing a plurality of shaped charges may include acharge tube. The means for locating a detonating cord proximate to ashaped charge may include a retainer fitting. The rotational means forsecuring the detonating cord to the shaped charge may comprise a baseportion with an opening adapted to attach to a shaped charge, a bodyportion adapted to accept a detonating cord, and a detonating cordretainer portion.

The embodiment disclosed above may be further modified such that thebase portion may have a flange adapted to engage a shaped charge. Thebase portion may have a cutout adapted to allow the base portion to snaponto a shaped charge. The body portion may further comprise a firstrectangular portion and a second rectangular portion substantiallyparallel to the first rectangular portion. The first rectangular portionmay be longer than the second rectangular portion. The detonating cordretainer portion may further comprise a first detonating cord retainer.The detonating cord retainer portion may further comprise a seconddetonating cord retainer. The first rectangular portion may contain afillet. The second rectangular portion may contain a fillet. The firstdetonating cord retainer may contain an arch. The second detonating cordretainer may contain an arch. The first detonating cord retainer and thesecond detonating cord retainer may be adapted to accept a detonatingcord at a first angle with respect to an axis formed by thesubstantially parallel first rectangular portion and the secondrectangular portion. The apparatus may be adapted to substantiallyrestrain the detonating cord when rotated a second angle.

An example embodiment may include an apparatus for use in a perforatinggun having a charge tube having a first end, a second end, an internalcavity, and a center axis. The charge tube has at least one chargecutout. The circular cutout has an axis that is perpendicular to theaxis of the charge tube. A retainer cutout corresponds to eachsubstantially circular cutout. The retainer cutout is located onehundred eighty degrees on the charge tube from the charge cutout. Atleast one adjacent locking cutout corresponds each retainer cutout. Theembodiment may include a second adjacent cutout for each retainercutout. Further, the at least charge cutout is may be a plurality ofcharge cutouts located along the length of the charge tube. Eachretainer cutout may have a shape adapted to only fit a retainer in apredetermined orientation. The charge tube may be adapted to fit ashaped charge device with a retainer fitting for each charge cutout andcorresponding retainer cutout.

Another example embodiment may include a shaped charge retainer having abase portion with an opening adapted to attach to a shaped charge, abody portion with a detonating cord cutout adapted to hold a detonatingcord, and a first retainer portion attached to the body portion adaptedto retain the detonating cord inside the detonating cord cutout. Theembodiment may include the base portion having an adaptor configured tosnap onto the end of a shaped charge. The embodiment may include thebase portion having a cutout adapted to allow the base portion to flex.The body portion may further comprise a second retainer portion adaptedto retain the denotation cord inside the detonating cord cutout. Thefirst retainer portion, the second retainer portion, and the detonatingcord cutout may combine to form a u-shaped detonating cord retainer. Thefirst retainer portion and the second retainer portion may both beintegral with the body portion. The first retainer portion may containan arch. The second retainer portion may contain an arch. The baseportion may include a thru slot. The embodiment may be adapted tosubstantially restrain a detonating cord from sideways movement.

Another example embodiment may include a shaped charge detonating cordretention system having a charge tube with a first axis and at least onecharge hole having a second axis perpendicular to the first axis and atleast one shaped charge retaining cutout coaxial with the second axis.The shaped charge retaining cutout is adapted to fit a detonating cordretainer in any angular orientation relative to the second axis.

Variations of the example embodiment may include it having a pluralityof charge hole cutouts and a corresponding plurality of shaped chargeretaining cutouts. Each charge hole cutout and corresponding shapedcharge retaining cutout may have a corresponding common axisperpendicular to the first axis. Each corresponding common axis may beparallel to each other or have a phase angle relative to the nextadjacent common axis. The detonating cord retainer may be adapted tointerface with the apex end of a shaped charge case.

The detonating cord retainer may have a base having a bottom end and atop end. A bore extends into the base from the bottom end. An aperturein the top end of the base is adapted to allow detonation communicationfrom the top end of the base into the bore. It also may have a firstretention arm having an inner face extending substantially orthogonallyfrom the top side of the base. It may have a second retention arm havingan inner face extending substantially orthogonally from the top side ofthe base. The inner face of the first retention arm is substantiallyparallel to and facing the inner face of the second retention arm. Theinner face of the first retention arm has a retention nub distal fromthe base extending toward the second retention arm. The first retentionarm and second retention arm are adapted to retain a detonating cord inproximity to the aperture. The inner face of the second retention armhas a retention nub distal from the base extending toward the firstretention arm. The example may have a circumferential ridge in the boreadapted to engage a corresponding groove in a shaped charge case. In thealternative, it may have a circumferential groove in the bore adapted toengage a corresponding ridge in a shaped charge case. The aperture mayextend from the top end of the body to the bore. The bore may extendthrough a portion of the top end of the body to form the aperture.

Another example embodiment includes a detonating cord retainer having afirst portion with a thru-hole having a first axis, a second portionlocated above the first portion, a truncated cone located above andcoaxially aligned with the first portion and the second portion. It mayfurther have a thru channel with a second axis perpendicular to thefirst axis. The first portion may be a cylindrical shape located coaxialwith the first axis. The second portion may be a cylindrical shapelocated coaxial with the first axis. The retainer may be composed ofplastic. The first cylindrical portion may be adapted to snap over anapex end of a shaped charge case. The first cylindrical portion may becomposed of two cylindrical halves. The truncated cone portion may havea u-shaped interface adapted to snap around a detonating cord. Theshaped charge retainer may be adapted to rotate in 360 degrees about theapex end of the shaped charge case. The second portion may have athru-slot along a first plane perpendicular to the first axis.

Another example embodiment includes a shaped charge retention systemhaving a shaped charge case with an apex end and an explosive dischargeend. It further has a charge tube with a center axis. A first pluralityof circular cutouts in the charge tube are adapted for interfacing witha shaped charge case apex end. A second plurality of circular cutouts inthe charge tube are located 180 degrees opposite of the first pluralityof cutouts about the charge tube axis. The embodiment includes adetonating cord. A substantially cylindrical retainer with a channeladapted to accept a detonating cord is included. The shaped charge caseis located within the charge tube such that the apex end is coupled to afirst circular cutout with the cylindrical retainer and the explosivedischarge end is located adjacent to a second circular cutout.

A variation of the example may include the cylindrical retainer beingcomposed of plastic. The cylindrical retainer may pivot about the shapedcharge apex in 360 degrees. The cylindrical retainer may further becoupled to the detonating cord. A plurality of shaped charges may beincluded. A plurality of cylindrical retainers may be included. Thechannel may have a u-shaped cutout.

Another example embodiment includes a shaped charge retainer having afirst portion, a first end having a truncated cone shape, a bottom end,with a slotted thru-hole passing through the first portion from thefirst end to the second end. It further includes a counter-bore in thebottom end having an axis. It further includes a second portion locatedabove the first portion. A truncated cone is located above the firstportion. The truncated cone has a channel with a second axisperpendicular to the first axis. The retainer may be composed ofplastic. The first portion may be adapted to snap over an apex end of ashaped charge case. The channel of the truncated cone portion may be au-shaped interface adapted to snap around a detonating cord. The shapedcharge retainer may be adapted to rotate in 360 degrees about the apexend of the shaped charge case. The bottom end may be circular, the firstportion may be cylindrical, or the second portion may be cylindrical.The first portion, second portion, and truncated cone are coaxial. Thefirst cylindrical portion may be composed of two cylindrical halves. Thesecond portion may have a thru-slot along a first plane perpendicular tothe axis.

The example may further include a shaped charge with a case, the casehaving an explosive end and an apex end adapted to interface with theshaped charge retainer. The apex end is located within the counter borein the bottom end. The shaped charge case may be connected to the shapedcharge retainer via the apex and counter bore interface. It may includea shoulder located on the bottom end. A charge tube may be capturedbetween the shoulder and a shaped charge case.

DESCRIPTION OF THE DRAWINGS

For a thorough understanding of the present disclosure, reference ismade to the following detailed description of the preferred embodiments,taken in conjunction with the accompanying drawings in which referencenumbers designate like or similar elements throughout the severalfigures of the drawing. Briefly:

FIG. 1 is a side cross sectioned view of a perforating gun.

FIG. 2 is a side cross sectioned view of a shaped charge that may beused in a perforating gun with a retainer fitting attached.

FIG. 3A is a detailed view of a retainer fitting.

FIG. 3B is a top view of a retainer fitting with a detonating cord inthe unlocked position.

FIG. 3C is a top view of a retainer fitting with a detonating cord inthe locked position.

FIG. 3D is a side view of a retainer fitting.

FIG. 3E is a bottom view of a retainer fitting.

FIG. 4 is a side view of a charge tube adapted for use with an exampleembodiment.

FIG. 5A is a perspective view of a detonating cord retainer.

FIG. 5B is a cross-section view of a detonating cord retainer.

FIG. 6 is a cross-section side view of a detonating cord retainerattached to a shaped charge case.

FIG. 7 is a perspective view of a detonating cord retainer.

FIG. 8 is a side view of a charge tube adapted for use with an exampleembodiment.

DETAILED DESCRIPTION OF EXAMPLES OF THE EMBODIMENTS

In the following description, certain terms have been used for brevity,clarity, and examples. No unnecessary limitations are to be impliedtherefrom and such terms are used for descriptive purposes only and areintended to be broadly construed. The different apparatus, systems andmethod steps described herein may be used alone or in combination withother apparatus, systems and method steps. It is to be expected thatvarious equivalents, alternatives, and modifications are possible withinthe scope of the appended claims.

Referring to an example shown in FIG. 1, a typical perforating gun 10comprises a gun body 11 that houses the shaped charges 12. The gun body11 contains end fittings 16 and 20 which secure the charge holder 18into place. The charge holder 18 in this example is a charge tube andhas charge holes 13, 19, and 23 that are openings where shaped charges12 may be placed. The charge holder 18 has retainer cutouts 31 that areadapted to fit a retainer fitting 30 in a predetermined orientation.Scallops 15, 21, and 22 provide a flat surface on the gun body 11 forthe explosive charge to penetrate through. The gun body 11 has threadedends 14 that allow it to be connected to a series of perforating guns 10or to other downhole equipment depending on the job requirements. Inthis example, the retainer fitting 30 is separate from the charge holder18, however in another variation of the embodiment, the retainer fitting30 may be integral to the charge holder 18. Each shaped charge 12 has anassociated retainer fitting 30 that secures each shaped charge 12 to thecharge holder 18 and the detonating cord 32. The detonating cord 32 runsthe majority of the length of the gun body 11 beginning at end cap 48and ending at end cap 49. The detonating cord 32 wraps around the chargeholder 18 as shown to accommodate the different orientations of theshaped charges 12. In this embodiment, the shaped charges 12 have anorientation that is rotated 60 degrees about the center axis of the gunbody 11 from one shaped charge to the next. Other orientations may havezero angle, where all of the shaped charges 12 are lined up. Otherorientations may have different angles between each shaped charge 12.This example using a 60 degree phase is illustrative and not intended tobe limiting in this regard.

Referring to an example shown in FIG. 2, the shaped charges 12 includesa shaped charge case 28 that holds the energetic material 26 and theliner 27. The shaped charge case 28 typically is composed of a highstrength metal, such as alloy steel. The liner 27 is usually composed ofa powdered metal that is either pressed or stamped into place. Themetals used in liner 27 may include brass, copper, tungsten, and lead.The retainer fitting 30 is secured to the apex end 46 of the shapedcharge case 28 by snapping into place over a flange on apex end 46. Theentire assembly 40 includes shaped charge 12 combined with retainerfitting 30. Alternatively, the retainer fitting 30 could be threadedonto the shaped charge case 28, secured with adhesive, snapped aroundthe full length of the charge case, or formed integrally with the chargecase. The fitting 30 could also be secured to the charge case 18 usingset screws, roll pins, or any other mechanical attachment mechanisms.Alternatively, shaped charge case 28 could be integrally formed toretainer fitting 30. This would result in a single component, thusreducing cost and complexity.

Referring to an example shown in FIG. 3A, this is a detail drawing ofthe retainer fitting 30. The retainer fitting has a first detonatingcord retainer 33 and a second detonating cord retainer 34. The retainerfitting 30 has a circular opening 35. The retainer fitting 30 has tworectangular base portions 36 and 37. Base portion 36 is longer than baseportion 37. Base portion 36 is parallel to base portion 37.

The adaptor 39 has a base slot 44, in this example it is perpendicularto the rectangular base portions 36 and 37. The base slot 44 allows someflexibility in the adaptor 39. In this example the adaptor 39 iscomposed of a plastic material that may deform without yielding. Thebase slot 44 aids in helping the adaptor 39 yield. This addedflexibility allows the adaptor 39 to snap over the apex end 46 of ashaped charge case 28 of FIG. 2.

In FIG. 3B the retainer fitting 30 has detonating cord retainers 33 and34. Retainer 34 has an edge 42 that is angled 45 degrees with respect tothe parallel axis of rectangular base portions 36 and 37. Retainer 33has an edge 43 that is also angled 45 degrees with respect to theparallel axis of rectangular base portions 36 and 37. Edge 42 and edge43 are parallel to each other, forming slot 40. Slot 40 is wide enoughto fit detonating cord 51 as depicted in FIG. 3B. Each of therectangular base portions 36 and 37 contain fillets 38 that are adaptedto accommodate the radius of a detonating cord 51.

In at least one example, detonating cord retainers 33 and 34 are shapedas arches as viewed from the side in FIG. 3D. The adaptor 39 has aninternal flange 47 designed to assist in attaching the retainer fitting30 to the shaped charge case 28 apex end 46. The procedure for securingthe detonating cord 51 is to first place it into slot 40 as shown inFIG. 3B. Then, rotating the retainer fitting 30 45 degrees detonatingcord retainers 33 and 34 force the detonating cord 51 against thefillets 38 as shown in FIG. 3C.

FIG. 3B shows the detonating cord 51 as it is initially placed in theretainer fitting 30. FIG. 3C depicts the detonating cord 51 as it sitsin the retainer fitting 30 after the retainer fitting 30 has beenrotated and locked into place on the charge holder 18. As seen in FIG.3E the retainer fitting 30 has an adaptor 39 which allows for theretainer fitting 30 to snap into place on the apex end 46 of the shapedcharge case 28 upon installation.

Referring to FIG. 4, the charge holder 18 has the retainer cutout 31 andlock cutouts 54. Installation may include snapping a retainer fitting 30on each shaped charge 12. The assembled shaped charge 12 with associatedretainer fitting 30 is then placed through the charge hole 23 of thecharge holder 18 until the retainer fitting 30 exits through theretainer cutout 31. The retainer fitting 30 has a lock block 45 shown inFIG. 3A. The charge holder 18 has a lock cutout 54 associated with eachretainer cutout 31. The retainer fitting 30 can be rotated until slot 40is aligned with the detonating cord 51 as shown in FIG. 3B. Thedetonating cord 51 is then placed into slot 40. Then the retainerfitting is rotated, or twisted, until the lock block 45 engages the lockcutout 54. Once twisted, the detonating cord 51 and retainer fitting 30will look as depicted in FIG. 3C. As can be seen in FIG. 4, the retainercutout 31 is shaped uniquely such that a retainer fitting 30 can onlyfit into the charge holder 18 in one specific angular orientation. Oncethe retainer fitting 30 is rotated to a second angular orientation itwill interfere with the shape of the retainer cutout 31, preventing theretainer fitting 30 from being able to disengage unless it is rotatedback to the original angular orientation.

The retainer fitting 30 has a lock block 45 that is adapted to fit intothe lock cutout 54 on the charge holder 18 as shown in FIG. 4. The lockblock 45 is engaged by twisting the retainer fitting until it reachesthe desired orientation whereby the lock block 45 and lock cutout 54 arealigned. Engagement of the lock block 45 with lock cutout 54 will keepthe retainer fitting 30 from rotating further. Alternatively, the lockblock 45 may be eliminated or replaced by other mechanical or frictionfit means, such as angling or texturing the undersides of the adaptor 39as shown in FIG. 3A. Another alternative to the embodiments disclosedmay include using the adaptor base 39 and combining it with the u-shapedupper portion 75 from the detonating cord retainer 50. The adaptor basemay also have different oblong shapes, including oval shapes,triangular, or other polygons, to allow the adaptor base 39 to lock intothe charge holder 18 when rotated.

As can be seen from the shape of the retainer cutout 31, it can onlyaccommodate the retainer fitting 30 in a specific orientation. Once theretainer fitting 30 has cleared the retainer cutout 31, it will beoriented to lay the detonating cord 51 along slot 42, as shown in FIG.3B. Then the shaped charge 12 and retainer fitting 30 assembly 40 isrotated, at least in this example, approximately 45 degrees. Rotatingthe assembly 40 causes the detonating cord 51 located with the slot 42to be locked into place against the fillets 38 and the cord retainers 33and 34, as shown in FIG. 3C. The arch design of retainers 33 and 34force the detonating cord 51 against the fillets 38 upon alignment.Further, once rotated 45 degrees, the retainer fitting is locked intothe charge holder 18 by the lock block 45 plugging into the lock cutout54. The retainer fitting 30 can be composed of materials common in theindustry, including metal and plastics. The retainer fitting 30 can bemanufactured using injection molding techniques, casting, rapidprototyping, machining techniques, or other common manufacturingtechniques known in the art.

Other alternatives to the embodiments disclosed include using a singlebase portion instead of the separate base portions 36 and 37.Alternatively, the base portion may have a different oblong shape suchas an oval, triangle, or other polygon. Another alternative may have theretainers 33 and 34 contact and secure to one and the other through afastening mechanism, allowing for a more secure connection between theretainer fitting and the detonation cord. Another variation may includeusing a circular base, with retainers that connect to one another,securing the detonation cord, and then using a circular adaptor suchthat the fitting could turn freely with respect to the charge case. Thisdesign would allow for optimal wiring of the detonation cord. Once thedetonation cord is in its final orientation, a set screw, resilienttabs, or other retaining device could be used to secure the fitting tothe case or to the shaped charge in order to prevent movement. In theembodiments disclosed above, two lock blocks 45 and two lock cutouts 54are disclosed, however more or fewer of either item could be used tosecure the retainer fitting to the charge tube. The fitting could bethreaded onto the charge case, secured with adhesive, snapped around thefull length of the charge case, or formed integrally with the chargecase. The fitting could also be secured to the charge case using setscrews, roll pins, or any other mechanical attachment mechanisms.Further, charge cases in the examples herein are shown as cylindricaldevices with cutouts, however other configurations are possible forholding shaped charges in a perforating gun. For example, a charge stripcan be used in which a long strip of metal containing holes for theretainer to engage with is used to hold a linear series of shapedcharges in a perforating gun. Other examples may include cylinders withone a single cutout for the retainer and no cutout for the shapedcharge. Another example may include a perforating gun that does not usea cylindrical charge holder to contain the shaped charges. Anotherexample may include a charge holder that is integral to the perforatinggun.

Another example embodiment is depicted in FIG. 5A and FIG. 5B. Thisdetonating cord retainer 70 has a base 71 with a through hole 74, amiddle portion 72 with a through slot 73, and a upper portion 75 that isshaped as a truncated conical with a u-shaped channel 76 that is sizedto snap onto a detonating cord. The detonating cord retainer 70 has afirst axis 102 aligning the base 71, middle portion 72, and upperportion 75. The u-shaped channel 76 also has an axis 101 that isperpendicular to the axis 102. The base 71 snaps onto the end of ashaped charge with the edge of the u-shaped channel 76 adapted to snapover a lip. The detonating cord retainer 70 can be secured to the shapedcharge, but still rotate to its desired orientation in order to snap toa detonating cord. The u-shaped channel 76 is designed to securely snaponto a detonating cord and restrict the movement of the detonating cord.In this embodiment the detonating cord could explode through the thinmaterial 77 between the u-shaped channel 76 and the thru slot 73,whereby the explosion would travel down the thru hole 74 and into theback of a shaped charge.

The thru slot 73 is perpendicular to axis 102. A clip may be placedthrough the thru slot 73 and adapted to engage a retainer cutout 93 asshown in FIG. 8, thus securing the detonating cord retainer 70 to acharge tube 90. Furthermore, detonating cord retainer 70 has a base 71that has a shoulder 121 capable of engaging the charge tube 90 in such away as to restrain the movement of the shaped charge along the axis 108,but allowing rotation about the axis 108. In the alternative, a thruhole or thru aperture could be located at 77 to facilitate explosivecommunication between the detonating cord and the shaped charge.

An alternative to the u-shaped channel 76 is a c-shaped cutout in whichthe channel 76 is rotated 90 degrees such that the detonating cord isaccepted from the side rather than the top as shown. The shoulder 78allows the retainer 70 to snap onto the apex end 60 of a shaped charge,as shown in FIG. 6.

In FIG. 6 the shaped charge case 58 is attached to the detonating cordretainer 50. The shaped charge case 58 is machined with an apex end 60.The apex end 60 has a lip 59. The detonating cord retainer 50 snaps overthe lip 59. Alternatively, the detonating cord retainer 50 could bethreaded onto the shaped charge case 58, secured with adhesive, snappedaround the full length of the shaped charge case 58, or formedintegrally with the shaped charge case 58. The detonating cord retainer50 could also be secured to the shaped charge case 58 using set screws,roll pins, or any other mechanical fasteners. The detonating cord 61 issnapped into the u-shaped cutout 56. In this example the detonating cordretainer 50 can freely rotate when attached to the shaped charge case58, however a set screw or other fastening device could be used toprevent rotation if desired. When the detonating cord 61 detonates theexplosion will puncture through the thin material 57 and enter thru hole64 of the shaped charge case 58. The explosion will then interact withthe explosive material 62 causing it to explode. The detonation ofexplosive material 62 will then transform liner 63 into a plasma jetcapable of puncturing out of the perforating gun. The thin material 57may be solid, it could also have a thru hole, perforations, a window orother aid that facilitates the explosion traveling from the detonatingcord 61 to the explosive material 62. Furthermore, in this embodimentthe u-shaped cutout 56 is depicted as having a gap between the tworetaining ends 65, however the gap could be narrower such that theretaining ends 65 touch each other either before or after the detonatingcord 61 is put into place. The detonating cord retainer 50 may beconstructed of plastic using for instance an injection molding processor a rapid prototyping process. The detonating cord retainer 50 in thisembodiment restricts the ability of the detonating cord 61 to movesideways, but it may allow the detonating cord 61 to move through thedetonating cord retainer 50 and allows for rotation of the detonatingcord 61 with respect to the shaped charge case 58.

Another example embodiment of a detonating cord retainer 80 is shown inFIG. 7. It is adapted to interface with the apex end of a shaped chargecase. Detonating cord retainer 80 includes a base 82 having a bottom end83 and a top end 88. A bore 81 extends into the base 82 from the bottomend 83. An aperture 89 in the top end 88 of the base 82 is adapted toallow detonation communication from the top end 88 of the base 82 intothe bore 81. A first retention arm 86 having an inner face 87 extendssubstantially orthogonally from the top end 88 of the base 82. A secondretention arm 84 has an inner face 110 extending substantiallyorthogonally from the top end 88 of the base 82. The inner face 87 ofthe first retention arm 86 is substantially parallel to and facing theinner face 110 of the second retention arm 84.

The inner face 87 of the first retention arm 86 has a retention nub 111distal from the base extending toward the second retention arm 84. Thefirst retention arm 86 and second retention arm 84 are adapted to retaina detonating cord in proximity to the aperture 89. The inner face 110 ofthe second retention arm 84 has a retention nub 112 distal from the baseextending toward the first retention arm 86. A circumferential ridge 113is located in the bore 81 adapted to engage a corresponding groove in ashaped charge case. The circumferential ridge 113 may also be acircumferential groove adapted to engage a corresponding ridge in ashaped charge case. The aperture 89 extends from the top end 88 of thebody 82 to the bore 81. The bore 81 may extend through a portion of thetop end 88 of the body 82 to form the aperture 89.

Another example embodiment may include a charge detonating cordretention system having a charge tube 90 as shown in FIG. 8 with a firstaxis 107. One or more charge holes 92, each having a second axis 108perpendicular to the first axis 107, are located along the charge tube90. Each charge hole 92 has a corresponding shaped charge retainingcutout 91 coaxial with the second axis 108. Each shaped charge retainingcutout 91 is adapted to fit a detonating cord retainer in any angularorientation relative to the second axis 108. Each second axis 108 may beparallel to each other or offset by a certain number of degrees aboutthe first axis 107 called a phase angle. For example, in FIG. 8 thephase angle is 60 degrees.

Although the embodiments have been described in terms of particularexamples which are set forth in detail, it should be understood thatthis is by illustration only and that the embodiments are notnecessarily limited thereto. Alternative embodiments and operatingtechniques will become apparent to those of ordinary skill in the art inview of the present disclosure. Accordingly, modifications of theembodiments are contemplated which may be made without departing fromthe spirit of the disclosure.

What is claimed is:
 1. A shaped charge detonating cord retention system comprising: a charge tube with a first axis and at least one charge hole having a second axis perpendicular to the first axis; and at least one shaped charge retaining cutout coaxial with the second axis, wherein the shaped charge retaining cutout is adapted to fit a detonating cord retainer in any angular orientation relative to the second axis.
 2. The apparatus of claim 1, further comprising a plurality of charge hole cutouts and a corresponding plurality of shaped charge retaining cutouts.
 3. The apparatus of claim 2, wherein each charge hole cutout and corresponding shaped charge retaining cutout has a corresponding common axis perpendicular to the first axis.
 4. The apparatus of claim 3, wherein each corresponding common axis is parallel to each other.
 5. The apparatus of claim 3, wherein each adjacent corresponding common axis has a pre-selected phase angle relative to the next adjacent common axis.
 6. The apparatus of claim 3 wherein the detonating cord retainer is adapted to interface with the apex end of a shaped charge case and further comprising: a base having a bottom end and a top end; a bore extending into the base from the bottom end; an aperture in the top end of the base adapted to allow detonation communication from the top end of the base into the bore; a first retention arm having an inner face extending substantially orthogonally from the top side of the base; a second retention arm having an inner face extending substantially orthogonally from the top side of the base; and wherein the inner face of the first retention arm is substantially parallel to and facing the inner face of the second retention arm.
 7. The apparatus of claim 6 wherein the inner face of the first retention arm has a retention nub distal from the base extending toward the second retention arm; and the first retention arm and second retention arm are adapted to retain a detonating cord in proximity to the aperture.
 8. The apparatus of claim 7 wherein the inner face of the second retention arm has a retention nub distal from the base extending toward the first retention arm.
 9. The apparatus of claim 6 further comprising a circumferential ridge in the bore adapted to engage a corresponding groove in a shaped charge case.
 10. The apparatus of claim 6 further comprising a circumferential groove in the bore adapted to engage a corresponding ridge in a shaped charge case.
 11. The apparatus of claim 6 wherein the aperture extends from the top end of the body to the bore.
 12. The apparatus of claim 6 wherein the bore extends through a portion of the top end of the body to form the aperture.
 13. A detonating cord retainer comprising: a first portion with a thru-hole having a first axis; a second portion located above the first portion; and a truncated cone located above and coaxially aligned with the first portion and the second portion and having a thru channel with a second axis perpendicular to the first axis.
 14. The apparatus of claim 13, wherein the first portion is a cylindrical shape located coaxial with the first axis.
 15. The apparatus of claim 14, wherein the second portion has a cylindrical shape located coaxial with the first axis.
 16. The apparatus of claim 15, wherein the retainer is composed of plastic.
 17. The apparatus of claim 15, wherein the first cylindrical portion is adapted to snap over an apex end of a shaped charge case.
 18. The apparatus of claim 15, wherein the first cylindrical portion is composed of two cylindrical halves.
 19. The apparatus of claim 15, wherein the truncated cone portion has a u-shaped interface adapted to snap around a detonating cord.
 20. The apparatus of claim 13, wherein the shaped charge retainer is adapted to rotate in 360 degrees about the apex end of the shaped charge case.
 21. The apparatus of claim 13, further comprising the second portion having a thru-slot along a first plane perpendicular to the first axis.
 22. A shaped charge retention system comprising: a shaped charge case with an apex end and an explosive discharge end; a charge tube with a center axis, having a first plurality of circular cutouts adapted for interfacing with a shaped charge case apex end and a second plurality of circular cutouts located 180 degrees opposite of the first plurality of cutouts about the charge tube axis; a detonating cord; and a substantially cylindrical retainer with a channel adapted to accept a detonating cord, wherein the shaped charge case is located within the charge tube such that the apex end is coupled to a first circular cutout with the cylindrical retainer and the explosive discharge end is located adjacent to a second circular cutout.
 23. The system of claim 22, wherein the cylindrical retainer is composed of plastic.
 24. The system of claim 22, wherein the cylindrical retainer can pivot about the shaped charge apex in 360 degrees.
 25. The system of claim 22, wherein the cylindrical retainer is further coupled to the detonating cord.
 26. The system of claim 22, further comprising a plurality of shaped charges.
 27. The system of claim 22, further comprising a plurality of cylindrical retainers.
 28. The system of claim 22, wherein the channel is a u-shaped cutout.
 29. A shaped charge retainer comprising: a first portion, a first end having a truncated cone shape, a bottom end, with a slotted thru-hole passing through the first portion from the first end to the second end; a counter-bore in the bottom end having an axis; a second portion located above the first portion; and a truncated cone located above the first portion and the second portion and having a channel with a second axis perpendicular to the first axis.
 30. The apparatus of claim 29, wherein the retainer is composed of plastic.
 31. The apparatus of claim 29, wherein the first portion is adapted to snap over an apex end of a shaped charge case.
 32. The apparatus of claim 29, wherein the channel of the truncated cone portion is a u-shaped interface adapted to snap around a detonating cord.
 33. The apparatus of claim 31, wherein the shaped charge retainer is adapted to rotate in 360 degrees about the apex end of the shaped charge case.
 34. The apparatus of claim 29, wherein the bottom end is cylindrical.
 35. The apparatus of claim 29, wherein the first portion is cylindrical.
 36. The apparatus of claim 29, wherein the second portion is cylindrical.
 37. The apparatus of claim 29, wherein the first portion, second portion, and truncated cone are coaxial.
 38. The apparatus of claim 35, wherein the first cylindrical portion is composed of two cylindrical halves.
 39. The apparatus of claim 29, further comprising the second portion having a thru-slot along a first plane perpendicular to the axis.
 40. The apparatus of claim 29, further comprising: a shaped charge with a case, the case having an explosive end and an apex end adapted to interface with the shaped charge retainer, wherein the apex end is located within the counter bore in the bottom end.
 41. The apparatus of claim 29, wherein the shaped charge case is connected to the shaped charge retainer via the apex and counter bore interface.
 42. The apparatus of claim 29, further comprising a shoulder located on the bottom end.
 43. The apparatus of claim 42, wherein a charge tube is captured between the shoulder and a shaped charge case.
 44. A detonating cord retainer comprising: a base having a bottom end and a top end; a bore extending into the base from the bottom end; an aperture in the top end of the base adapted to allow detonation communication from the top end of the base into the bore; a first retention arm having an inner face extending substantially orthogonally from the top side of the base; a second retention arm having an inner face extending substantially orthogonally from the top side of the base; and wherein the inner face of the first retention arm is substantially parallel to and facing the inner face of the second retention arm.
 45. The detonating cord retainer of claim 44 wherein the inner face of the first retention arm has a retention nub distal from the base extending toward the second retention arm; and the first retention arm and second retention arm are adapted to retain a detonating cord in proximity to the aperture.
 46. The detonating cord retainer of claim 45 wherein the inner face of the second retention arm has a retention nub distal from the base extending toward the first retention arm.
 47. The detonating cord retainer of claim 44 further comprising a circumferential ridge in the bore adapted to engage a corresponding groove in a shaped charge case.
 48. The detonating cord retainer of claim 44 further comprising a circumferential groove in the bore adapted to engage a corresponding ridge in a shaped charge case.
 49. The detonating cord retainer of claim 44 wherein the aperture extends from the top end of the body to the bore.
 50. The detonating cord retainer of claim 44 wherein the bore extends through a portion of the top end of the body to form the aperture.
 51. A detonating cord retainer comprising: a base having a bottom end and a top end; a bore extending into the base from the bottom end; an aperture in the top end of the base adapted to allow detonation communication from the top end of the base into the bore; a first retention arm having extending substantially orthogonally from the top side of the base and having an end distal from the base; and a second retention arm having an inner face extending substantially orthogonally from the top side of the base and having an end distal from the base.
 52. The detonating cord retainer of claim 51 wherein the end of the first retention arm has a retention nub extending toward the second retention arm.
 53. The detonating cord retainer of claim 52 wherein the end of the second retention arm has a retention nub extending toward the first retention arm.
 54. A shaped charge comprising: a case with an apex end and an explosive end and an axis; a substantially conical liner located within and coaxially with the case; an explosive material located between the liner and the case; a detonating cord retainer adapted to interface with the apex end of the case further comprising: a base having a bottom end and a top end; a bore extending into the base from the bottom end; an aperture in the top end of the base adapted to allow detonation communication from the top end of the base into the bore; a first retention arm having an inner face extending substantially orthogonally from the top side of the base; a second retention arm having an inner face extending substantially orthogonally from the top side of the base; and wherein the inner face of the first retention arm is substantially parallel to and facing the inner face of the second retention arm.
 55. The detonating cord retainer of claim 54 wherein the inner face of the first retention arm has a retention nub distal from the base extending toward the second retention arm; and the first retention arm and second retention arm are adapted to retain a detonating cord in proximity to the aperture.
 56. The detonating cord retainer of claim 55 wherein the inner face of the second retention arm has a retention nub distal from the base extending toward the first retention arm.
 57. The detonating cord retainer of claim 54 further comprising a circumferential ridge in the bore adapted to engage a corresponding groove in a shaped charge case.
 58. The detonating cord retainer of claim 54 further comprising a circumferential groove in the bore adapted to engage a corresponding ridge in a shaped charge case.
 59. The detonating cord retainer of claim 54 wherein the aperture extends from the top end of the body to the bore.
 60. The detonating cord retainer of claim 54 wherein the bore extends through a portion of the top end of the body to form the aperture. 